This invention relates to devices and methods for providing liquid-tight seals between a pipe, housing, or other hollow structure, and concrete or other cement-like mixtures in which the structure is embedded. More particularly, it relates to providing liquid-tight seals about structures penetrating spray cast or poured walls of swimming pools, tanks, sewerage containers, dams, retaining walls, basement walls, foundations, and other cementitious castings meant to confine or channel the flow of liquid.
When pools are constructed of concrete, gunnite, other cement-containing compositions or similar curable mixtures, it is often necessary to create holes in the walls accommodating pipes, drains, and variously shaped housings for underwater lighting, pool skimming appliances, and related structure. It has been found that the concrete does not always adhere to the surface of these structures, but tends to slump away during curing. Water may thereafter seep along the surface of the structure into or through and behind the wall, causing erosion and other damage to the pool. This problem is particularly troublesome with PVC pipe and housings of other polymeric material which are now widely used in such installations because of their low cost and high durability.
In the past, such leaks have been attended to, for instance, by packing the spaces where the leak occurs with an appropriate material. By the time a leak is recognized and packed, significant damage to the cast structure or its immediate environment may have occurred. Furthermore, this type of packing is difficult to install and is often only a temporary solution to the problem. Metallic fittings disposed in tight-fitting engagement about pipes have been tried in an effort to solve this problem. However, casting the wall about such fittings has not succeeded in preventing formation of leaks.
It is an object of this invention to provide a device and method for forming a liquid-tight seal between the exterior surface of a structure and the concrete or other substance in which the structure is embedded. Another object is to provide a liquid-tight seal which is both simple and inexpensive to install and manufacture. Still another object is to provide a convenient method of locating and maintaining the location of pipes, housings, and other structures which are to be embedded in castings, during pouring or spraying of the curable composition about the structure. These and other objects of the invention will be apparent from the description, drawing, and claims which follow.